This invention relates generally to transmissions for motor vehicles, and relates more particularly to a planetary gear carrier thrust washer system for an automatic transmission.
Motor vehicles generally require a power plant such as an internal combustion engine, a power train and wheels. The internal combustion engine produces force by the conversion of the chemical energy in a liquid fuel into the mechanical energy of motion (kinetic energy), and the power train transmits this resultant force to the wheels to provide movement of the vehicle. The main component of the power train is typically referred to as the transmission. Engine torque and speed are converted in the transmission and delivered to the driven wheels in accordance with the vehicle""s tractive-power availability. The vehicle""s transmission is also capable of controlling the direction of rotation being applied to the wheels, so that the vehicle may be driven both forward and backward.
Transmissions are generally referred to as manually actuated or automatic transmissions. Manual transmissions generally include driver controlled and actuated mechanisms for coupling rotating gears to produce different ratio outputs to the drive wheels. Automatic transmissions are designed to take automatic control of the frictional units, gear ratio selection and gear shifting. A thorough description of general automatic transmission design principals may be found in xe2x80x9cFundamental Of Automatic Transmission and Transaxles,xe2x80x9d Chrysler Corporation Training Manual No. TM-508A. Additional descriptions of automatic transmissions may be found in U.S. Pat. No. 3,631,744 and U.S. Pat. No. 4,289,048. Each of these patents is hereby incorporated by reference.
A conventional automatic transmission includes a hydrodynamic torque converter to transfer engine torque from the engine crankshaft to a rotatable input member of the transmission through fluid-flow forces. The transmission also includes frictional units which couple the rotating input member to one or more members of a planetary gearset. Other frictional units, typically referred to as brakes, hold members of the planetary gearset stationary during the flow of power. These frictional units are usually brake clutch assemblies or band brakes. The drive clutch assemblies can couple the rotating input member of the transmission to the desired elements of the planetary gearsets, while the brakes hold elements of these gearsets stationary. Such transmission systems also typically provide for one or more planetary gearsets in order to provide various ratios of torque and to ensure that the available torque and the respective tractive power demand are matched to each other.
The planetary gearsets may be provided with thrust washers. These thrust washers must be manually assembled during production, and are generally direction sensitive for proper function and may be sensitive to dimensional tolerances.
The present invention is a carrier assembly for an automatic transmission. The carrier assembly comprises a cup and a plate connected to the cup. The cup has a first outside diameter, and the plate has a second outside diameter greater than the first outside diameter. The plate also has a channel extending inwardly from a circumference of the plate. A thrust washer having a tab is keyed into the channel.
Accordingly, it is an object of the present invention to provide an automatic transmission planetary carrier pinion gear thrust washer designed for reliable positioning, and having a positive anti-rotation feature lending itself to simple automated assembly at high volume production.
Another object of the present invention is to provide a carrier assembly of the type described above that may be automatically assembled.
Another object of the present invention is to provide a carrier assembly of the type described above that is relatively insensitive to dimensional tolerances.